The invention relates generally to hydraulic control devices and, more particularly, to a device which protects a drive from excess loading conditions.
Such overload conditions originate from many factors; for example, additional hydraulic pumps may be suddenly connected to the drive or obstructions in the outlet pipes may develop, etc. However, the known devices for protecting a drive from such overload conditions have not proven altogether reliable or satisfactory in practice.
A common drawback of such prior-art devices is that there is great difficulty in establishing a predictable relationship between a predetermined desired speed for the drive and a predetermined cross-section for a throttle-type flow-restrictor. At present, one lever is provided for the adjustment of the desired rpm of the drive and another lever is provided for the adjustment of the flow-restrictor cross-section. It has proven very difficult to coordinate the movement of these levers so that the desired relationship between these two quantities can be employed in protecting the drive from undesirable overload conditions.